1. Field of the Invention
The present invention relates to a toner for developing electrostatic latent images and a production method thereof, an electrostatic latent image developer, an image forming method, and an image forming apparatus, used when developing a latent image formed by an electrophotographic method, an electrostatic recording method, and the like, using a developer.
2. Description of the Related Art
Impurities, in particular low molecular weight constituents having an aroma, which are included in a toner for developing electrostatic latent images (hereinafter, referred to as “toner”) used in a method such as the electrophotographic method for visualizing image information through an electrostatic image, causes an undesirable situation when using the toner, such as giving discomfort in the form of an odor at the time of opening the toner container.
As a method of fixing a toner onto the surface of a copying paper in the fixing step, a pressure fixing method, a heat fixing method, and the like are used. Examples of a heat fixing method include an oven fixing method, a flash fixing method, a pressure fixing method, and a heated roller fixing method. In an electrophotographic copier and the like, in general, the heated roller fixing method is widely used. In the method, the heating efficiency when the surface of a heated roller and the sheet image to be fixed are fusion bonded onto a sheet to be fixed, is excellent, enabling rapid fixing. In particular, the method is very effective as a fixing method at the time of high speed copying.
However, in the heat fixing method, since the toner image is heated, trace constituents, in particular the abovementioned low molecular weight constituents having an aroma, and the like included in the toner, are released into the atmospheric air, which may give an unpleasant odor to the user in some cases. Furthermore, recently, with the miniaturization of copiers and printers, there are more and more occasions where such devices are familiarly used in offices and the like. Moreover, there are increased occasions where they are used in ordinary homes, resulting in an increase in cases where the odor generated from the toner, brings discomfort to the user.
One of the causes of an odor being generated from an electrophotographic device, is ozone generation due to corona discharge. However, by contact charging methods such as roller charging, brush charging, and the like, or by technological innovation such as a corona discharger which minimizes the ozone generation, the ozonic odor has been greatly reduced, but relatively, cases where toner odor caused by the toner brings discomfort have increased. Moreover, since ozone, odor, and the like are absorbed into the mainframe, there is also a case where a filter and the like are attached. However, with a filter there is the problem of periodic exchange and the like in order to maintain the deodorizing function, which is also a disadvantage in terms of production cost.
Other methods of reducing the odor originating in the toner include a conventional method of reducing impurities in the binder resin. For example, in Japanese Unexamined Patent Publication No. Sho 64-70765, Japanese Patent Application Laid-Open (JP-A) Nos. 64-88556, and 8-328311, there is proposed a method of reducing odor by reducing residual monomers in the binder resin.
Moreover, assuming that only a reduction in the volatile constituents included in the resin is not sufficient, since odor generation can be caused by volatiles that have been generated during the toner production process by decomposition of chemically unstable substances, a trace of which is included in the raw material, then as a countermeasure against the odor of the overall final toner product, there is disclosed a technique of removing the odor of the raw materials, for example in JP-A Nos. 7-104515, and 7-104514.
Moreover, assuming that the causative substance of odor is oxidation products of benzaldehyde included in the toner, then for example as disclosed in JP-A No. 8-171234, an approach to reduce the contents of benzaldehyde has been made.
Meanwhile, for example in JP-A No. 9-230628, a scheme has been devised to improve the odor, and at the same time to prevent the negative effect on the fixity, by reducing the usage of alkymercaptan (one of the causative substances of odor generation) which is a molecular weight control agent for resin, and is essential for the basic function of the toner, while controlling it to the minimum requirement.
Moreover, for example in JP-A No. 3-105350, an approach has been made to add alkylbetaine compounds into the toner, as a substance which reacts with odorous substances and absorbs them. Furthermore, for example in JP-A No. 2002-123038, an approach has been made to add phytoncides, catechines, and metallophthalocyanines into the toner. Moreover, for example, in JP-A No.2002-131980, an approach is described to add macrocyclic lactone and macrocyclic ketone compounds with the object of neutralizing the odor of a chain transfer agent in the polymerization toner resin.
However, these methods can not avoid the absorption and the like of other active toner constituents due to the structure of the compound, which tends to result in deterioration of the key qualities as a toner, such as the charging characteristic and the like.
Furthermore, for example in JP-A No. 2-240663, there is described a method of bringing deodorizer and toner into contact for 5 hrs or more in the crushing and classifying steps, so as to deodorize it. However, in this method, the production takes a long time, and the odor generated after completing the production is not necessarily sufficiently reduced.